MP Brendan Horan used his mother's credit card to pay for accommodation while attending a race meeting and campaigning in New Plymouth, it is alleged.

He also allegedly used the card to buy a cheap suit, to stay at a motor lodge in Hastings and to pay a veterinary bill for his horse.

The Sunday Star-Times last week obtained hundreds of pages of Horan's mother's bank statements going back to 2000. They show that Olwen Horan's cards were being hammered while she was terminally ill and bedridden before her death in August.

New Zealand First leader Winston Peters said yesterday he relied on the statements and other information to sack Horan, and again called on him to resign from Parliament.

"He's got no business being in Parliament now. He's got no mandate and no business trying to tough this out. It's appalling."

Horan continues to deny wrongdoing but did not return calls to address the latest allegations.

Olwen Horan signed an amendment to her will a month before she died authorising her executor to retrieve money loaned to her Mt Maunganui-based son or "taken by misadventure".

The Star-Times can reveal her credit card was used at the Dawson Motel in New Plymouth on May 27, 2011. Horan was in New Plymouth overnight on May 26 to attend a race meeting, and made a speech to a Grey Power meeting on behalf of Peters when Peters' flight was diverted due to bad weather.

At that point, Horan had yet to be elected to Parliament.

In August 2011, the card was used to buy a suit at Barkers menswear in Papamoa for $99. Horan had boasted at the time about it being a bargain. The card was used at the store again in July this year to buy $990 worth of clothes.

Horan also used his mother's card to pay $300 for accommodation at the Omahu Motor Lodge in Hastings in October 2007.

Former co-owner Patricia Thurlow told the Star-Times: "He wrote in my guest book something stupid like ‘the whole time I stayed the sun didn't shine'."

In 2001, the credit card was used to pay a $375 bill at a veterinary clinic in Edgecumbe. At the time, Horan had a horse that had been injured at his sister's property nearby.

There was also considerable expenditure in Hamilton - at service stations, supermarkets, cafes and Parallel Imported - at a time when Horan had a Gold Buyers franchise in the city.

On other occasions Olwen Horan's eftpos and credit cards were used in Auckland, Whakatane, Rotorua, Gisborne and for accommodation in Christchurch and Mt Maunganui.

The bank statements contain about 10 years' worth of expenditure that Olwen Horan was concerned about, and which some family members claim was unauthorised.

Transactions included:

More than $15,000 withdrawn from a single Westpac ATM machine at Bayfair shopping centre over about six years. Withdrawals were made in amounts ranging from $100 to $700, including more than one withdrawal in a day. Thousands of dollars were withdrawn from other ATMs in the Mt Maunganui area.

At least 50 TAB transactions over the years, usually in the $50 to $100 range. There were also numerous transactions at the Papamoa Tavern, where Brendan Horan was a regular.

At least $16,000 of cash withdrawals were made from Olwen Horan's Visa Gold card. The amounts were usually for $500 or $1000. A further $10,000 in cash was withdrawn from banks. There are also concerns about cheques totalling about $180,000 that have become the main focus of forensic accountants.

Late last year and early this year Horan was making fortnightly $500 payments into his mother's account. He says he was paying back a loan. Around $4500 was paid, according to the statements seen.

Thousands of dollars were spent at menswear stores as far afield as Te Awamutu, service stations and supermarkets around Bay of Plenty and Waikato, a golf driving range opposite the TAB at Bayfair, furniture, hardware, appliance stores and liquor outlets.

The Star-Times revealed last weekend that the family had offered to settle the dispute if Horan agreed to a $40,000 reduction in his share of his mother's estate. He offered $25,000, which was unacceptable to the family.

Horan last week told Radio Live his relationship with his mother was such that if he ever required anything, "all I needed to do was ask".

He said there may have been cheques from his mother, but no-one had shown him specifics.

"She may have given me some cheques... mothers tend to do that.

"And if she did, so what?

"But it's a long time ago and so I have to see the specifics of the cheques... that's why I've got my lawyer and that's what we're doing," he said.

Peters said the information revealed today by the Star-Times "would compel someone to act, and I did. I saw enough to utterly convince me I had to act straight away. I have no regrets".

He said critics who said he acted too soon "don't know what they're talking about".

Peters said of Horan's alleged use of his mother's cards: "I can't conceive how he could do that. When I got the information I was stunned by it, and seriously brassed off."

It was also revealed that Horan had been using a taxpayer-funded phone to call the TAB.